Prepositions of Time

Master the use of in, on, and at for time expressions, plus other common time prepositions like before, after, during, and since.

in / on / at for Time

Preposition	Used with	Examples
in	months, years, seasons, centuries, parts of day	in January, in 2010, in summer, in the morning
on	days, dates, specific days with parts of day	on Monday, on 5 May, on Monday morning
at	clock times, festivals/holidays, specific points	at 7 o'clock, at Christmas, at noon, at night

Tip Easy trick: at is the smallest/most precise → clock times. on is medium → days, dates. in is largest → months, years, seasons.

Other Important Time Prepositions

Preposition	Meaning	Example
before	earlier than	Finish before midnight.
after	later than	She called after dinner.
during	throughout a period	He fell asleep during the film.
since	from a point in the past until now	I've lived here since 2018.
for	duration of time	I've been waiting for two hours.
until / till	up to a point	I'll stay until Friday.
by	not later than	Submit the report by Monday.
from … to/until	showing a range	The shop is open from 9 to 5.
within	inside a time limit	I'll reply within 24 hours.
ago	before now	I started school three years ago.

since vs for

since	for
starting point: since 2020, since Tuesday	duration: for three years, for a week
I have lived here since* 2020.*	I have lived here for* four years.*

Real world: event invitation

The party starts at 7 pm on Saturday, 12th June. Please arrive by 7:30. The venue is open from 6:30 until midnight. See you there!

Real world: timetable notice

The museum is open from Monday to Saturday, in the morning at 9 am. It is closed on Sundays and during national holidays. Last entry is at 4:30 pm.

Real world: assignment deadline email

Please submit your essay by Friday. I haven't received your work since last Monday. You have been in this class for three months — this is important.

Tip Time prepositions are essential in everyday English: invitations ("at 7 pm on Saturday"), school timetables ("closed on Mondays"), email deadlines ("submit by Friday"), and calendars. Getting in/on/at right makes your English sound natural and precise.

Practice Problems

Fill in: The museum opens ___ 9 in the morning.

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The museum opens at 9 in the morning.

Fill in: She was born ___ 5th September.

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She was born on 5th September.

Fill in: We are going on holiday ___ July.

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We are going on holiday in July.

since or for? — I haven't seen him ___ last year.

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since (a starting point: last year)

since or for? — They have been friends ___ ten years.

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for (a duration: ten years)